str1 = "我最喜欢的玩具是"
str2 = "乐高"
print(str1 + str2)

num = 10
str3 = "依然"
print("{0}年后，我在大街上碰到幼儿园的伙伴“小胖”，没想到他那体型{1}还是老样子，成了“大胖”。".format(num, str3))

str4 = "Wish all the best wishes for you."
print(str4.upper())

str5 = "HAPPY BIRTHDAY"
print(str5.lower())

str6 = "you are my friemd"
print(str6.replace("friemd", "friend"))
